Study Links Autism With Antidepressant Use During
Pregnancy

A cautiously worded study
based on data collected in Sweden has found that “in utero exposure to both
selective serotonin reuptake inhibitors (S.S.R.I.’s) and nonselective
monoamine reuptake inhibitors (tricyclic antidepressants) was associated
with an increased risk of autism spectrum disorders, particularly without
intellectual disability.”

The Swedish medical birth register (which
contains data on current drug use reported by mothers early in their
pregnancies), along with a system of publicly funded screenings for autism
spectrum disorders and extensive national and regional registers of various
health issues, make a detailed, population-based case-control study possible
— one that controls for other variables like family income, parent
educational level, maternal and paternal age and even maternal region of
birth (all factors the authors note have been previously associated with
autism).

This is the second study in two years to associate antidepressant use
during pregnancy with an increased incidence of autism in exposed children.
An earlier, smaller
study in California also found a modest increase in risk. The
Sweden-based study could not (and did not) exclude the possibility that it
was the severe depression, rather than the use of antidepressants, that
created the association, but the smaller California study (which considered
only S.S.R.I.’s) found “no increase in risk” for mothers with a history of
mental health treatment in the absence of prenatal exposure to S.S.R.I.’s.

The authors of the current study took a very cautious approach to their
findings:

The results of the present study as well as the U.S. study present a
major dilemma in relation to clinical advice to pregnant women with
depression. If antidepressants increase the risk of autism spectrum
disorder, it would be reasonable to warn women about this possibility.
However, if the association actually reflects the risk of autism
spectrum disorder related to the nongenetic effects of severe depression
during pregnancy, treatment may reduce the risk. Informed decisions
would also need to consider weighing the wider risks of untreated
depression with the other adverse outcomes related to antidepressant
use. With the current evidence, if the potential risk of autism were a
consideration in the decision-making process, it may be reasonable to
think about, wherever appropriate, nondrug approaches such as
psychological treatments. However, their timely availability to pregnant
women will need to be enhanced.

Others working in the field are more inclined to draw a line between the
prenatal drug exposure and the increased risk of autism. “It really
shouldn’t come as that much of a surprise given that numerous animal studies
have shown that exposure during development leads to changes in the brain
and changes in behavior — often that mimic autism,” said Dr. Adam C. Urato,
assistant professor of obstetrics and gynecology at the Tufts University
School of Medicine and chairman of the department of obstetrics and
gynecology at MetroWest Medical Center in Framingham, Mass. (Dr. Urato
obviously didn’t speak in links, but you can find the animal studies he
refers to here and
here.)

“And why should it surprise us that medications that can change brain
chemistry and function might alter the development of the brain and behavior?”
Dr. Urato argues that the risks of antidepressant use during pregnancy
outweigh what he sees as the
limited benefits.

One conclusion that is simple to draw is that it’s extraordinarily
difficult for a pregnant woman with clinical depression to find some
definitive answer about what’s best for her in her situation. I’ve spoken to
other researchers in the past who have described for me how difficult it is
to put together a study that separates the risks of depression itself in
pregnancy from the risks, if any, of the drugs used to treat it. As the
researchers in Sweden note, it’s unlikely that conclusive evidence on this
issue will ever be available.

If you’ve been pregnant with clinical depression, where did you go to
find the information and advice you needed?

Updated | April 23, 2013: In re-reading this post, I’ve
realized I should have included exactly how “modest” the increase in autism
rates was (an increase that, again, wasn’t “caused” by prenatal exposure to
either form of antidepressant but rather associated with it). In this study,
the increase was just 0.6 percent — worthy of discussion, not decision (and
certainly not condemnation). I’ve been surprised by the number of readers
who, in the comments, took this cautiously observed association and blew it
up into something rather larger. Happily, the entire study (unlike many) is
freely available at the link above. You’ll find other, more extensive
discussions of what these numbers do and don’t mean for individual women
here and
here.